The role of nitric oxide (NO) in biology has received much attention over the past several years. Indeed, NO has been shown to play a fundamental role in several key biochemical processes including blood pressure control and neurotransmission. However, NO is also implicated in a variety of neurodegenerative disorders such as Alzheimer's and Parkinson's disease. Unfortunately: unraveling the various biological functions of NO is often deterred by a lack of methodology to visulaize it directly and provode spatial and temporal information about its distribution. In the present study we intend to synthesize fluorescent NO sensor molecules for visual marking of NO with the goal of discerning its function(s) in the various physiological processes. In this regard we will take advantage of the fluorescence quenching properties of Cu(ll) centers when coordinated to fluorescent ligand moieties representing the OFF state of the sensor. In presence of NO, the Cu(ll) center will be reduced to Cu(l) resulting in a diamagnetic species turning the fluorescence ON and signalling the presence of this neurotransmitter. The current approach provides an improved methodology to sense NO and will find wide use for imaging NO in biological samples.